This invention relates to a socket contact for use in a female connector of paired electrical connectors used in an electronic appliances for connection between two boards, and more particularly to a method for producing such a socket contact.
A hitherto used socket contact will be explained by referring to FIGS. 4A and 4B and 5A and 5B. FIG. 4A illustrates in a perspective view an electrical connector 40 using socket contacts 42 of the prior art. FIG. 4B is a perspective view showing the socket contact 42 of the prior art. FIG. 5A illustrates in a side view the socket contact 42 of the prior art with a mating contact 22 shown in imaginary lines inserted therein. FIG. 5B is a side view of a socket contact 421 which is a modification of the socket contact 42 to have a narrower pitch of socket contacts and a mating contact 22 in imaginary lines inserted therein.
In general, the electrical connector 40 mainly consists of an insulator 12 and socket contacts 42 or 421 as well-known. The insulator 12 is an electrically insulating plastic material and formed by the well-known injection molding technique or the like. The socket contact 42 or 421 is made of a metal and formed by the well-known press working or the like.
The socket contact 42 or 421 consists of four portions, that is, contact portions 18 to contact a mating contact 22, a fixing portion 16 to be fixed to an insulator 12, a connection portion 14 to be connected to a board or the like (not shown) and connecting portions 20 for respectively connecting the contact portions 18 to the fixing portion 16. The contact portions 18, connecting portions 20, fixing portion 16 and connection portion 14 are arranged in this order. The contact portions 18, connecting portions 20 and fixing portion 16 are referred to as contact pieces 19.
In producing the socket contact 42 of the prior art shown in FIG. 4B, first a metal plate strip is punched to form a flat socket contact whose two contact pieces 19 arranged in parallel with each other are then bent inwardly into a U-shaped form.
In the state that such processes have been completed, the center axis of the contact portions 18 adapted to contact the mating contact 22 is shifted from the bottom surface 15 of the fixing portion 16 in consideration of the radius of the mating contact 22 plus the required clearance, thereby preventing the distal end of the mating contact 22 from contacting the bottom surface 15 of the fixing portion 16 as shown in FIG. 5A.
In order to shift the center axis of the contact portions 18 from the bottom surface 15 of the fixing portion 16 by a value corresponding to the radius of the mating contact 22 plus the required clearance, a pitch of socket contacts is required to be more than 2 mm, these socket contacts being continuous with each other in the state immediately after a metal plate strip is punched to form a series of flat socket contacts. In other words, according to the prior art the width (refer to numeral 17 in FIG. 2A) of the contact portions of the flat socket contact, which have not been bent, is required to be more than 2 mm in order to prevent the distal end of the mating contact from contacting the bottom surface of the fixing portion.
In assembling a connector by inserting socket contacts into an insulator, it has been a common practice to temporarily manually insert the continuous socket contacts 42 into a series of insertion apertures (not shown) formed in the insulator 12 and then to finally insert the separated socket contacts into the insulator 12 by means of a jig (not shown).
With the recent miniaturization of electrical (electronic) appliances, electrical connectors have been strongly required to be more miniaturized. In order to more miniaturize the electrical connectors, it is absolutely necessary to make the pitch of contacts as small as possible. With the contacts having such a construction and assembled in the manner described above, however, it is impossible to make a series of socket contacts having a pitch less than 2 mm, which is a problem to be solved.
If socket contacts were separately inserted into the insulator 12 one by one, a more miniaturized electrical connector could be obtained even if the continuous socket contacts in the state punched from a metal strip do not have a pitch less than 2 mm. However, such an assembling will increase the material cost and man-hour with resulting high production cost.
Moreover, even if a miniaturized electrical connector easy to assembly can be obtained with a smaller pitch of socket contacts fulfilling the requirement of the recent market, there would be tendency of the distal end of the mating contact 22 to contact the bottom surface 15 of the fixing portion 16 of the socket contact, which is a further problem to be solved. Such contact between the mating contact and the bottom surface of the fixing portion of the socket contact will cause the damage of both the contacts, resulting into defective contact therebetween and, in worst cases, requiring the replacement of the male and female connectors or boards. Such a replacement will increase the production cost.